I want to build an RC car so I can familiarize myself with the machine shop at my school. The car will be simple and I have everything figured out except the differential.

 

I want to put an electric brushless motor on the rear axle, but I don't think I could just have 1 drive shaft for both rear wheels and gear it up that way. I need to figure out how to make a differential so the outer wheel can rotate faster during turns.

 

I know most RC cars have some system like this but I haven't been able to figure out how it works. Also I can't seem to figure out how to invent one myself so I need some links/ideas.

 

The tools available to me are: precision lathes, 2-axis mills, water jet cutter, bandsaw, grinders, drills, hand tools, etc...

 

Any help appreciated.

I don't think you need a differential in a small "simple" RC car, but one way to achieve a similar effect would be to use two motors, one on each rear wheel.

This link seems to explain how it works pretty well.

Check especially page 2 with the animated explanation.

Take a look at "ball differentials" -- This article has some pictures:

http://www.tamiyaclub.com/showroom_model.asp?cid=43390&sid=5475

Hmm...

 

nevermind I guess, I invented my own. Got the idea last night, this design uses 3 gears and a lever. Basically if one wheel is slowed down, it will transfer the rest of the torque to the other wheel. Super simple, works on relative motion between two gears.

 

Now I just need to learn how to draw in Solidworks so I can mill these out.